1. Field of the Invention
The present invention related to an aqueous ink comprising at least one disazo or polyazo dye, and also relates to an inkjet recording ink and an inkjet recording method.
2. Background Art
The coloring agent used in an inkjet recording ink is required to have high solubility or dispersibility in a solvent, enable high-density recording, provide good color hue, be resistant to light, heat and active gases in the environment (for example, oxidative gases such as NOx and ozone, and SOx), exhibit excellent fastness to water and chemicals, ensure good fixing property to an image-receiving material and less bleeding, give an ink having excellent storability, have high purity and no toxicity, and be available at a low cost. However, it is very difficult to find out a coloring agent satisfying these requirements in a high level. In particular, a black dye providing good color hue for compensating a color corresponding to a longer wavelength side in a black color, exhibiting fastness to light, humidity and heat, and exhibiting fastness to oxidative gases in the environment such as ozone when the image is printed on an image-receiving material having an ink-receiving layer containing a porous inorganic white pigment particle, are strongly demanded.
Azo coloring matters comprising a sulfur-containing heterocyclic coupler as a coupling component of an azo dye have been heretofore disclosed, for example, in JP-A-54-46226 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), JP-A-54-139638, JP-A-60-235866, JP-A-2001-207092, JP-A-59-152957, JP-A-6-143838 and JP-A-6-143839. However, azo dyes described in these publications all are insufficient in the fastness to light, heat, humidity, active gases in the environmental and the like.